Convection Lesson

Multiple Select

In which states of matter can convection take place in?

• solid

• liquid

• gas

• vacuum

Fill in the Blanks

Can convection take place in vacuum?

Open Ended

Describe how heat is transferred by convection when a beaker of liquid is heated.

Describe how heat is transferred by convection when a beaker of liquid is heated.

​Suggested answer:

When the bottom of a liquid is heated, it expands and becomes less dense than the surrounding cooler liquid. The heated part of the liquid rises to the top of the liquid. The cooler liquid at the top, being denser, sinks. A Convection Current is formed. So heat is transferred by convection.

Describing convection

Open Ended

Describe how heat is transferred by convection when a gas is heated.

Describe how heat is transferred by convection when when a gas is heated.

​Suggested answer:

When the bottom of a gas is heated, it expands and becomes less dense than the surrounding cooler air. The heated part of the air rises to the top. The cooler air at the top, being denser, sinks. A Convection Current is formed. So heat is transferred by convection.

Describing convection

Fill in the Blanks

Can convection take place in solids?

Open Ended

Explain why convection cannot take place in a solid.

Fill in the Blanks

Cold air tends to

because it is more dense than the air around it.

Fill in the Blanks

Hot gases and liquids float because they are less

that the gases and liquids around them.

Multiple Choice

Which of the following is an application of convection?

• The movement of heat through a metal pan to the food.

• The use of ice box to keep drinks cool.

• The sea breeze that blows from sea to land.

• The use of wool blanket to keep the body warm.

Multiple Choice

Which is the best position to place the heating element in an electric heater?

• A

• B

• C

• D

Open Ended

Explain why is D the best position to place the heating element.

Multiple Choice

Which of the following correctly shows the direction of convection currents in water?

• A

• B

• C

• D

Multiple Choice

Warm air rises and the cool air sinks demonstrates this type of heat transfer. 

• conduction
• convection
• radiation
• Insolation 

Multiple Choice

Which of the following is an example of convection?

• A hair dryer is drying up your hair.
• When the AC or heater changes the temperature.
• When a car engine turns hot after being turned on.
• When you are making soup and the water is rising and lowering.

Multiple Choice

What is the definition of CONVECTION

• When heat transfers through waves.
• When heat transfers from objects that are touching.
• a  hot liquid or air that  expands, becomes less dense, and rises or becomes more dense, and sinks.
• Heat traveling from the sun

Multiple Choice

On a hot day, the upstairs rooms in a house are usually hotter than the downstairs rooms. Why?

• Cool air is less dense than hot air.
• Warm air rises and cool air sinks
•  The roof insulation warms the air
•  Heat rises